Shoe stiffener



Q 9, converted from a fibrous, to a gelatinous or Patented Jan. 27, 1931 PATENT OFFICE ERNEST LIONNE, OF SWAMPSCOTT, MASSACHUSETTS SHOE STIEIENER Application filed September 24, 1928. Seria1 No. 308,082.

This invention relates to a sheet material adapted especially for use as stiifeners for shoes asbox toe stiifeners, counters and the like.

A shoe stifiener and especially a box toe stiffener is composed of a sheet of material that can be made limp and pliable so that it readily can be shaped to conform to the last of the shoe during the lasting operation and will ultimately become permanently stiff and hard whereby to support and preserve the lasted shape of the adjacent part of the shoe.

There is a certain class of shoe stiffeners, which is composed of textile material im- 5 pregnated with a nitro-cellulose, as celluloid,

of shoes.

adapted for lasting by immersing them in a suitable softening agent for the nitro-cellulosic material, and which are adapted to become hard and stifi as soon as the solvent hasv evaporated therefrom. This class of stifiener has many desirable characteristics which especially adapt it for uselin the better grades Itis however relatively expensive. Many attempts have been made to devise a stiffener of the above class which can be manufactured cheaply but the stiffeners thus produced have been commercially unsatisfactory as they were either mechanically weak so that they could not be lasted readily, or relatively impervious so that it took a long time for the solvent to penetrate and soften the stiffener, or bulky so that they occupied too much space in the shoe, or too expensive to be commercially practicable.

It is an'object of the present invention to provide a sheet material especially adaptedfor use for stifieners for shoes, and a stiffener made from such material, that can besoftened quickly by the application of a suitable softening agent and can be shaped into the desired form on the lastand will hardeninto the shaped form when the solvent has e'va'porated and will have-increased stillness and can be cheaply made by paper makingmethods and apparatus. j

In accordance with this invention, 1 provide a paper sheet which in its preferred 7 form is composed of fibres at-"leastsome of which are soluble and are capable of being colloidal and film forming nature by the apcellulose fibres which have been formed by the action of acids thereon, such as cellulose acetate or cellulose nitrate. I prefer to use cellulose nitrate fibres, however, by'reason of 1 their' relative cheapness. Such fibres are known as pyroxyline and are cotton fibres of 'a relatively low degree .of nitration. The

degree of nitrati on does not particularly matter however so long as the nitrated fibres are quickly soluble in a suitable cheap solvent;

A further object of the invention is the combination of a sheet containing soluble and insoluble fibres, and a softening agent there-- for which contains a solvent for the soluble fibres and a softener for the insoluble fibres, whereby the sheet can be rendered extremely pliable.

In carrying out my invention, I mix, in the ordinary beater for making aper, a suitable proportion of the soluble bres with other paper making fibres, such as rag stock, or any other suitable and well known paper making fibres or mixture of fibres. The roportion of soluble fibres to the paper ma 'ng fibres can vary in accordance with the particular requirements demanded of the finished product. For a finished sheet which is 'adapted to be exceptionally stiff'and rlgid after its treatment with the solvent, I can make the paper sheet entirely from soluble fibreswit-houtgthe admixture thereto of insolublefibres.- For the usual box toe stiifener,

however, ,a mixture of fifty per cent soluble fibres and fifty per-cent insoluble fibres gives very satisfactory results. The fibres aresubusual paper making fibres, tend to become shorter than the paper making fibres and so will not felt so well with the paper making fibres in the paper making machine if the beating action is unduly prolonged. After the beating action has been completed, a paper sheet is formed of the fibres in the usual manner in any suitable paper making machine as a Fourdrinier, or a cylinder, ma-

chine. On the paper making wire, the fibres form into a sheet wherein the soluble and insoluble fibres are felted together, the soluble fibres being interlaced with the insoluble fibres. The sheet thus formed can be made of any desirable thicknessin accordance with any usual or desirable paper making practice. The sheet is then dried to remove surplus water therefrom but not to a degree to modify the structure or physical characteristics of any of the fibres. The sheet is also preferably lightly calendered in order to smooth the surfaces of the sheet but care istaken that the sheet is not compacted to gether by severe pressure, as the sheet is "required to be porous and solvent-absorbent to such degree thatit can be rapidly penetrated by the solvent for the soluble fibres.

Shoe stifl'eners of the usual form are adapt ed to be cut from the sheet prepared as above described. Immediately prior to the lasting, the stifieners are treated with, as immersed in, a softening agent for the stiifeners, which, due to the marked porosity of the sheet, rapidly penetrates it and comes in intimate contact with practically all of the fibres of the stiffener. The softening agent contains a solvent for the soluble fibres of the stifiener, which solvent, in the case of pyroxyline fibres, can be acetone, a mixture of alcohol and ether, ethyl-acetate, or any one of a number of the well known commercial solvents therefor. The softening agent, in accordance with this invention, also contains a liquid, as water, which is capable of being absorbed by the insoluble fibres. The action of the solvent is to soften and at least partially to dissolvethe soluble fibres of'the stiffener and to convert them to a collodial or jelly form and consequently to increase the pli-.

ability of the stiffener. The'action of the water is to soften the insoluble fibres and thus to render them more pliable. The combina-' tion of the solvent and the water is thus to increase the pliability ofthe stifl'ener over the action of one of these alone. The action of the softening agentcan be regulatedin an obvious manner to accord with the amount of soluble fibres" in the sheet and the uses to which the sheet is to be put. c

The amount of water in the softening agent preferably is small, as not greatly in excess of ten per cent. A large amount of water is detrimental as its presence in the insoluble fibres prevents the film formed of the soluble fibres from adhering strongly thereto.

Broadly considered, the practice of adding water to a solvent for celluloid-containing or impregnated stifi'eners has been in use for many years for the purpose of moderating the action of the solvent and to prevent the softened stiffeners from adhering to each other while-in the mulling box. The water however can not act to soften the fibrous body of the impregnated stiffener as the fibres are coated with the celluloid film which acts as a protective cover to keep the water away from the fibres.

The solvent. impregnated sheet is then lasted into the shoe between the upper and the lining in the usual manner and is adapted to stay on the last until the solvent has evaporated. Due to the evaporation of the solvent and also due to some extent to the lasting pressure, the colloidal pyroxyline is caused to be dispersed throughout the stiffener and to occupy the voids between and overlie and surround and become attached to the insoluble fibres of the stiffener and thus to appear as a hard relatively inflexible film in the dry stiffener. Due to the fact that the soluble fibres are dissolved or softened and the film formed thereof occupies the spaces between the insoluble fibres, the hardened stiffener is materially thinner than the'stiflz'ener before being subjected to the action of the solvent. That is an advantageous feature since the shoe in which such a stiffener is incorporated can have a trimmer appearance than with the usual impregnatedtype of stiffener. The degree to which the stiffener is reduced in thickness obviously depends upon the relative proportions of soluble and insoluble fibres of which it is composed.

. In addition to the above described advantageous qualities possessed by the sheet it also has the advantage of being economical in use as the waste material remaining after the stifi'eners have been cut from the large sheet can be used again, the waste material being placed in the beater with new paper making and pyroxyline fibres and beaten up and formed into a sheet. I find that seventy parts of new mate'riahwhich is composed of thirty-five parts each of cotton' batting and 'pyroxyline, and thirty parts of waste material forma satisfactory sheet'for shoe stiffener purposes.

In the drawing, Fig. 1 is a plan view of a a suitable volatile solvent for at least one of solvent has been removed the constituents of the sheet and which is adapted to be shaped into a form other than that in which it was made and to retain said form permanently when the solvent has evaporated, said sheet being composed of felted fibres, at least some of which are capable of being dissolved in a suitable solvent therefor and of being converted to a colloidal'form and when the solvent has evaporated to form a hard relatively inflexible film which embraces and is attached to the insoluble fibres and holds the sheet permanently to. the shape imparted to it, the dry treated sheet beingthinner than the sheet before the application of the solvent thereto.

3. A shoe stiffener composed of a paper sheet of felted paper making fibres, at least some of which are soluble in a suitable solvent tively inflexible film which embraces and is fibres when the om the sheet. .4. A shoe stiffener composed of a paper attached to the remaininigr sheet formed of'felted paper makin fibres I some of which-are soluble in a suita le solvent "and are capable-of being converted by the solvent from a fibrous to a'colloidal form and others of which are insoluble in and are unaffected by the solvent, the converted soluble fibres'existingin the treated sheet as a hard, relatively inflexible film which embraces and is attached to the insoluble fibres afterthe solvent has been removed'from the sheet.

. 5. A shoe stiffener composed of a paper a sheet of felted pyroxyline and other paper to, and bonds together the other papermaking fibres when the solvent has been removed from the sheet.

6. A shoe stiffener comprising a paper sheet composed at least in part of felted pyroxyline fibres which are capable of being converted from a fibrous to a colloidal form by the action of a suitable solvent therefor and of forming a hard and relatively inflexible film when the solventhad disappeared from the stiffener.

7 The combination of a shoe stiffener comprising a sheet formed ofv felted soluble and insoluble fibres, and a softening agent for the stiffener composed of a solvent or the soluble fibres and a liquid which is absorbed by and softens the insoluble fibres.

8. The combination of a shoe stiifener comprising a sheet formed of felted soluble and insoluble fibres, and a softening agent for the stiffener composed of a solvent for the soluble fibres and a liquid which is absorbed by and softens the insoluble fibres, which liquid comprises water in an amount which is not materially in excess of ten per cent. of the solvent. a

9. A sheet composed of felted fibres, at least some of which are soluble in a suitable 'solvent and are capable of being converted least some of which are capable of being converted to a colloidal form and thereafter of existing in the sheet as a film. i

In testimony whereof, I- have signed my name to this specificatio v ERNEST LIONNE.

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